Implement rtty in rio.c, rename to rtty.c

1 files changed, 123 insertions, 0 deletions

diff --git a/rtty.c b/rtty.c
new file mode 100644
index 0000000..9f64c6d
--- /dev/null
+++ b/rtty.c
@@ -0,0 +1,123 @@
+#include <err.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/select.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#define MAXBUF 2048
+
+int
+main(int argc, char *argv[])
+{
+	char bufin[MAXBUF], bufout[MAXBUF], *bi, *bo, in[30], **nargv, out[30];
+	fd_set rfds0, rfds1;
+	int fdin, fdout, i, n;
+	struct timeval tv;
+
+	/* Create named pipes. */
+	sprintf(in, "/var/tmp/rtty.in.%d", getpid());
+	sprintf(out, "/var/tmp/rtty.out.%d", getpid());
+	if(mkfifo(in, 0644) == -1 || mkfifo(out, 0664) == -1)
+		if(errno != EEXIST)
+			err(1, "mkfifo");
+
+	if(fork() == 0){
+		/* Redirect standard in, out. */
+		if(!(fdin = open(in, O_RDONLY)))
+			err(1, "open");
+		if(!(fdout = open(out, O_WRONLY)))
+			err(1, "open");
+		dup2(fdin, 0);
+		dup2(fdout, 1);
+
+		/* Create new argument vector. */
+		if(!(nargv = malloc(sizeof(char *)*(argc+1))))
+			err(1, "malloc");
+		nargv[0] = "ssh";
+		nargv[1] = "-tt";
+		for(i = 1; i < argc; i++)
+			nargv[i+1] = argv[i];
+		nargv[argc+1] = NULL;
+
+		/* Exec into ssh. */
+		execvp("ssh", nargv);
+		err(1, "execvp");
+	}
+
+	if(!(fdin = open(in, O_WRONLY)))
+		err(1, "open");
+	if(!(fdout = open(out, O_RDONLY)))
+		err(1, "open");
+
+	dprintf(fdin, "export TERM=tty43 PAGER=cat EDITOR=ed\n");
+
+	FD_ZERO(&rfds0);
+	FD_ZERO(&rfds1);
+
+	tv.tv_sec = 0;
+	tv.tv_usec = 1;
+
+	for(;;){
+		/*
+		 * User input is read from standard in and copied the
+		 * input pipe. It is saved in bufin for later use.
+		 */
+		FD_SET(0, &rfds0);
+		if(select(0+1, &rfds0, NULL, NULL, &tv) > 0){
+			n = read(0, bufin, MAXBUF);
+			bufin[n] = 0;
+			dprintf(fdin, "%s", bufin);
+			fflush(stdout);
+		}
+
+		/*
+		 * System output is read from the output pipe and copied
+		 * to standard out for the user to see.
+		 */
+		FD_SET(fdout, &rfds1);
+		if(select(fdout+1, &rfds1, NULL, NULL, &tv) > 0){
+			n = read(fdout, bufout, MAXBUF);
+			if(!n) continue;
+			bufout[n] = 0;
+
+			/*
+			 * Bufin and bufout are copied to the temporary
+			 * pointers bi and bo. Bo is incremented in order
+			 * to skip any potential repetition of the command
+			 * given by the user on standard in. (It is assumed
+			 * that the typed command fits in bufin, i.e. is
+			 * not larger than MAXBUF.)
+			 */
+			bi = bufin;
+			bo = bufout;
+			for(;;){
+				if(*bo == '\n'){
+					bo++;
+					break;
+				}
+				if(*bo == 13){
+					bo++;
+					continue;
+				}
+				if(*bi != *bo){
+					bo = bufout;
+					break;
+				}
+				bi++; bo++;
+			}
+
+			/*
+			 * Bo is printed and bufin is cleared, so as not
+			 * to perform the skip again, incorrectly.
+			 */
+			printf("%s", bo);
+			fflush(stdout);
+			bufin[0] = 0;
+		}
+	}
+
+}